Arab in country without borders (5)
I believe the answer is:
omani
'arab' is the definition.
(someone from Oman)
'country without borders' is the wordplay.
'country' becomes 'Romania' (European country).
'without borders' indicates the central letters (the letters on the sides of the word are removed).
The centre of 'romania' is 'OMANI'.
'in' is the link.
(Other definitions for omani that I've seen before include "Gulf native" , "From an Arabian country, capital Muscat" , "Naomi (anag) -- from Muscat?" , "Speaker of Arabic" , "Middle East national" .)